JPH11325149A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology to use a burp valve built in a rod guide arranged on one end of a shock absorber in which the burp valve can discharge a gas mixed with a hydraulic fluid so as to be returned to a place where a gas in a storage chamber is filled while maintaining an appropriate liquid-tight sealing while the shock absorber is in operation. SOLUTION: A shock absorber is provided with a uni-directional valve or a burp valve 52. The uni-directional valve or the burp valve 52 is arranged in a liquid passage extending between an upper working chamber 20 and a storage chamber 18 of the shock absorber. The liquefied gas in the upper working chamber 20 is accumulated in the fluid passage until a sufficient pressure to open the uni-directional valve 52 is accumulated. When the gas pressure reaches a specified value, the uni-directional valve 52 is opened, and the accumulated gas is discharged and returned to the storage chamber 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic damper or a shock absorber for use in a vehicle suspension. More particularly, the invention relates to a hydraulic damper or shock absorber with a pressure tube and a storage tube.

[0002]

2. Description of the Related Art A shock absorber uses an all-moving piston without a compression base valve and a high-pressure gas contained in a gas chamber formed between a pressure pipe and a storage chamber. Burp valves are capable of discharging gas mixed with oil by itself.

[0003] Prior art hydraulic dampers or shock absorbers have a working cylinder adapted to be mounted at one end to a springless part of the vehicle. A piston is slidably arranged in the cylinder,
The inside of the cylinder is separated into an upper working chamber and a lower working chamber. A piston rod is attached to the piston,
One end of the piston rod emerges from the working cylinder and is attached to the sprung part of the vehicle. A first valve device is arranged in the piston to generate a damping force during the extension stroke of the piston relative to the working cylinder. Also, a second valve device is disposed within the piston to generate a damping force during the compression stroke of the piston with respect to the working cylinder.

[0004] Some shock absorbers include a storage chamber cylinder concentrically disposed about the work chamber to form a storage chamber between the storage cylinder and the work cylinder. The reservoir is partially filled with hydraulic liquid and the rest of the cylinder is filled with pressurized gas. The amount of liquid in the storage chamber depends on the position of the piston in the working cylinder. Since the piston rod is only on one side of the piston, the movement of the piston in the working chamber is
It requires a storage room to receive and move the liquid volume, referred to as the rod volume.

During the stroke of the piston in the working chamber, gas from the storage chamber is mixed with the hydraulic fluid. In order for the shock absorber to operate properly, it is desirable to discharge this mixed gas from the hydraulic fluid.

[0006]

SUMMARY OF THE INVENTION The present invention provides a technique using a burp valve incorporated in a rod guide located at one end of a shock absorber. The burp valve allows the gas mixed with hydraulic fluid to be exhausted back to the storage chamber's gas-filled location during operation of the shock absorber while maintaining proper fluid tightness. I do.

[0007] Other advantages and objects of the present invention will become apparent to one skilled in the art from the following detailed description, claims, and drawings.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings of the present invention. Referring to the drawing,
Like reference numerals designate the same or corresponding parts throughout the several views. FIG. 1 shows a shock absorber, which is designated by the reference numeral 10 and which comprises a rod guide with a unique burp valve according to the invention. The shock absorber 10 includes the entire discharge piston 1
2, a piston rod 14, a pressure tube 16 and a storage chamber tube 18. The piston 12 connects the pressure pipe 16 to the upper working chamber 20 and the lower working chamber 2.
Divide into two. The piston rod 14 is
And exits from the pressure tube 16 and the storage tube 18 for attachment to the vehicle sprung structure in a manner known in the art. The pressure tube 16 is filled with hydraulic fluid moving between the upper working chamber 20 and the lower working chamber 22 during movement of the piston 12 and the piston rod 14 relative to the pressure pipe 16. The flow of liquid through the piston 12 between the chambers 20 and 22 of the pressure line 16 is controlled by the compression valve assembly 2
4 and the extension valve assembly 26. Valve assembly 2
4 and 26 are the piston 12 and the piston rod 1
4 is attenuated.

[0009] A reserve tube 18 surrounds the pressure tube 16;
A storage chamber 28 is formed together with the pressure pipe 16. Storage tube 18
Is adapted to be mounted on a vehicle unsprung structure known in the art. During the stroke of the piston 12 and the piston rod 14, different volumes of hydraulic fluid enter and exit the upper working chamber 20, as opposed to entering and exiting the lower working chamber 22. The difference in volume is due to the piston rod 14 being located only in the upper working chamber 20 and not in the lower working chamber 22. This difference in the volume of the liquid is known as the "rod volume". The "rod volume" of this liquid is compensated by the liquid located in the storage chamber, which flows into and out of the storage chamber as needed. The storage chamber 28 is partially filled with hydraulic fluid and partially filled with compressed gas, the level of hydraulic fluid being determined by the position of the piston 12 in the pressure tube 16. The fully mobile piston 12 eliminates the need for a base valve between the storage chamber 28 and the lower working chamber 22.

During the stroke of the piston 12 in the pressure tube, the compressed gas in the storage chamber 28 mixes with the hydraulic fluid in the storage chamber 28. A portion of this mixed gas is returned to the compressed gas portion of the storage chamber 28 and a portion of the mixed gas is
Enter 2. This mixed gas is supplied from the lower working chamber to the valve assembly 24.
And 26 evenly into the upper working chamber 20.
Upon entering the upper working chamber, the gas mixture is combined to create a pocket of compressed gas in the upper working chamber 20. In prior art shock absorbers, these pockets of compressed gas accumulate near the top of the shock absorber and adversely affect the operation of the shock absorber due to insufficient damping during the extension stroke of the piston 12 relative to the pressure tube 16. There is a fear.

The present invention is directed to a unique rod guide 50 that incorporates a perv valve assembly 52. Rod guide 50
Are located at the ends of the pressure tube 16 and the storage tube 18 from which the piston rod 14 extends. Rod guide 50
Is attached to the pressure tube 16 and the storage tube 18 to form a rod bore 54 through which the piston rod 14 extends.
The piston rod bearing 56 guides the movement of the piston rod 14 with respect to the rod guide 50. Lubrication passage 58
Supplies hydraulic fluid from the upper working chamber 20 to the sealing device 60 that seals the inner chamber of the shock absorber 10 through the rod guide 50.

The burp valve assembly 52 has an annular chamber 62, a radial passage 64, an annular groove 66, and an elastomeric sealing ring 68. An annular chamber 62 is disposed on the piston rod bearing 56 and has an annular groove 66 through a radial passage 64.
Connected to. An elastomeric sealing ring 68 is disposed within the groove 66 and when it is disposed within the groove 66 is sized to stretch and close to seal the radial passage. The annular groove 66 passes through the annular space 70 disposed between the rod guide 50 and the storage chamber tube 18 to store the storage chamber 2.
It communicates with 8.

The burp valve assembly 52 removes accumulated gas by “discharging” the accumulated gas into the storage compartment 28 as the shock absorber moves through the extension movement. During the extension movement of the shock absorber 10,
The liquid pressure in the upper working chamber 20 is higher than the liquid pressure in the storage chamber. This causes a pressure drop across the rod guide 50. Gas stored on the piston 12 in the upper working chamber 20 is pushed between the piston rod 14 and the piston rod bearing 56 toward the annular chamber 62. Annular chamber 62 is connected to storage chamber 28 through radial passage 64, annular groove 66, and annular gap 70. The trapped gas accumulates in the radial passage 64 until enough pressure is accumulated to bias the spring force created by the inherent hoop stress of the elastomeric sealing ring 68. When sufficient pressure builds up in the radial passage 64 to bias the spring force of the elastomeric seal ring 68, the seal ring 68 exits the radial passage,
The trapped gas is released into the storage room 28.

During the compression stroke of shock absorber 10, piston 12 and piston rod 14 move downward, creating a higher pressure in storage chamber 28 than in upper working chamber 20. The high pressure in the storage chamber 28 is added to the spring force of the elastomeric sealing ring 68 to ensure that the radial passage 64 is sealed. The sealing of the radial passage 64 prevents gas in the storage chamber 28 from entering the upper working chamber 20 through the radial passage 64.

While the above detailed description describes the preferred embodiment of the invention, it is understood that modifications, changes and variations may be made without departing from the scope and fairness of the appended claims. I can do it.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view showing a shock absorber having a rod guide with a unique burp valve according to the present invention.

FIG. 2 is an enlarged side sectional view of the rod guide with the unique burp valve shown in FIG. 1;

FIG. 3 is an enlarged sectional view of the piston assembly shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Shock absorber 12 Piston 14 Piston rod 18 Storage room 20 Upper working room 22 Lower working room 24 Compression valve assembly 26 Extension valve assembly 28 Storage room 50 Unique rod guide 52 One-way valve or burp valve 56 Piston rod bearing 58 Lubrication Passage 64 Radial passage 66 Annular groove 68 Elastomer sealing ring 70 Annular gap

Continuation of the front page (71) Applicant 591004504 500 North Field Drive, Lake Forest, Illin ois 60045, United States of America (72) Inventor David Steed 43551, Ohio, United States 43551, Meadowwood Drive, Pellisburg, United States 72) Inventor Michael Zebolsky 309, Pottawatamy Street, Tikamso, 49286, Michigan, USA

Claims (15)

[Claims] A pressure pipe forming a pressure chamber; a piston disposed in the pressure chamber and dividing the pressure chamber into an upper working chamber and a lower working chamber; and controlling a fluid flow through the piston. A valve assembly disposed in the piston, a storage tube surrounding the pressure tube and forming a storage chamber with the pressure tube, and fixed to the pressure tube and the storage tube and closing the upper working chamber A rod guide having a piston rod hole formed therein; a piston rod fixed to the piston and passing through the piston rod hole of the rod guide; and a fluid passage extending between the upper working chamber and the storage chamber. And a one-way valve disposed in the shock absorber. 2. The shock absorber according to claim 1, wherein the passage has an annular chamber disposed between the piston rod and the rod guide. 3. The shock absorber according to claim 2, wherein the passage includes a flow passage between the upper working chamber and the annular chamber. 4. The shock absorber according to claim 2, wherein said passage includes a radial passage passing through said rod guide. 5. The shock absorber according to claim 4, wherein said one-way valve comprises an elastomer ring surrounding a rod guide and closing said radial passage. 6. The shock absorber according to claim 5, wherein the rod guide has an annular groove, and the elastomer ring is disposed in the annular groove. 7. The shock absorber according to claim 1, wherein the passage includes a radial passage passing through the rod guide. 8. The shock absorber according to claim 7, wherein said one-way valve comprises an elastomer ring surrounding a rod guide and closing said radial passage. 9. The shock absorber according to claim 8, wherein the rod guide has an annular groove, and the elastomer ring is disposed in the annular groove. 10. The shock absorber according to claim 1, wherein the one-way valve comprises an elastomer ring surrounding a rod guide and closing the radial passage. 11. The rod guide includes an annular groove,
The shock absorber according to claim 10, wherein the elastomer ring is disposed in the annular groove. 12. The shock absorber according to claim 1, wherein the passage has a flow passage disposed between the piston rod and the rod guide. 13. The shock absorber according to claim 12, wherein said passage includes a radial flow passage extending between said flow passage and said upper working chamber. 14. The shock absorber according to claim 13, wherein said one-way valve comprises an elastomer ring surrounding a rod guide and closing said radial passage. 15. The rod guide includes an annular groove,
The shock absorber according to claim 14, wherein the elastomer ring is disposed in the annular groove.